1. Field of the Invention
This invention relates generally to a gear shifting mechanism for an automotive power transmission and more particularly to a mechanism of this type that provides a reverse gear inhibitor and a backup light switch combined in a single unit.
2. Description of the Prior Art
The gear shifting mechanism to which the present invention is directed is specifically of the type that furnishes a reverse idler gear to be moved into driving engagement with the reverse drive gear of the transmission input shaft. A gear selector shaft is manually operated to change the speed ratio of the transmission and to select reverse gear operation.
The gear shifting mechanisms of manually operated power transmissions are generally provided with means adapted to prevent accidential movement of the gear shift levers into positions that would shift the gears to reverse mode of operation when the vehicle operator intends to move the gear shift lever between forward drive gear positions. Inadvertent engagement of the reverse drive gear during forward mode of operation and particularly at high speed would produce catastrophic damage to the transmission and could risk vehicle and passenger safety as well. Known arrangements operative to prevent this inadvertent reverse gear engagement include the use of complicated means for shifting into reverse gear. When shifting between gears, the shift selector shaft is brought to a neutral plane before an engagement with either a forward drive gear or the reverse gear can occur. To avoid inadvertent and accidental reverse gear engagement, the selector shaft in certain prior art devices is required to be pushed downwardly toward the floor of the vehicle or pulled upwardly and then moved from this position into the reverse gear position. Additional known means to avoid accidental reverse gear engagement include requiring that the shift selector, in addition to being moved to the direction of the reverse gear, have buttons, which the drive must push before engaging reverse gear. Use of these techniques, therefore, encumbers the vehicle operator with the complicated and intricate manipulatory steps when shifting gears.
In manually operated transmissions, it is important when shifting between forward gears not only that the vehicle operator avoid placing the selector shaft in a reverse position but also that the shifting mechanism itself positively prevents inadvertent reverse gear engagement regardless of the position of the selector shaft.
Present day vehicles typically provide a warning to vehicular traffic and occasionally to the operator of the vehicle that the transmission is set for reverse operation. This indication is given outside the vehicle by way of the backup light usually mounted in the rear taillight assembly and within the vehicle by a warning light mounted on the dashboard within view of the vehicle operator. It is important in the operation of these warning signals that they be positive and serve to produce the required warning when the vehicle is set for reverse operation.
Gear shift mechanisms of the type herein described have previously included means associated with the shift selector shaft that require the vehicle operator to operate the shaft by applying some motion to the shaft when passing into reverse gear that is not identical to the motion given the shaft when forward gear ratios are selected.